Key damper installation

[Highbeam]

Now that I know my flue temperatures I’m going to try a key damper to hold some of that heat in. Lowe’s has the imperial brand for like 8$. My fancy flue probe temperature meter thing is at 18” above the stove.

How close should the damper be to the stove or the probe? Too close to the stove might melt the damper, too close to the probe might bugger up the probe temperature readings. Are either of these valid concerns?

Currently, to get the stove above 600 I need to run flue temps up near 900.

Thanks!

 

[bholler]

Now that I know my flue temperatures I’m going to try a key damper to hold some of that heat in. Lowe’s has the imperial brand for like 8$. My fancy flue probe temperature meter thing is at 18” above the stove.

How close should the damper be to the stove or the probe? Too close to the stove might melt the damper, too close to the probe might bugger up the probe temperature readings. Are either of these valid concerns?

Currently, to get the stove above 600 I need to run flue temps up near 900.

Thanks!

You probably have to be at least 3.5" below the probe so the damper plate doesn't hit it. You won't melt the damper. No concern there. So I would probably go to about a foot off the stove. And 900 is pretty high a damper will probably make quite a difference

 

[Highbeam]

You probably have to be at least 3.5" below the probe so the damper plate doesn't hit it. You won't melt the damper. No concern there. So I would probably go to about a foot off the stove. And 900 is pretty high a damper will probably make quite a difference

Tear down starting. I stole the diamond brand damper from a duravent brand double wall appliance adapter. Made in Iowa.

 

[moresnow]

Tear down starting. I stole the diamond brand damper from a duravent brand double wall appliance adapter. Made in Iowa.

Is that a vintage piece? The company sure is! Let us know what your results are with this little endeavor. Curious minds want to know

 

[Highbeam]

Holy smokes. After 8 years, the slip section of single wall does not like to collapse and then gets stuck closed! Eventually got it with some lube and a hammer but while wiping all of the pipes down I did manage to remove lots of paint. Looks like I’ll need to repaint at end of season.

Since I had it apart, I swept the sections with an old fashion poly brush. Nice and brown, crunchy powder.

Damper is in. The seam on the single wall sometimes prevents full 360 degree turning but that’s okay. Kind of a nice stopper. Damper at 12” above stove, probe at 18”.

I need to clean up. What a messy job. Then we’ll see how this thing works. I have no manometer so it will be just experimental.

 

[Gearhead660]

Now that I know my flue temperatures I’m going to try a key damper to hold some of that heat in. Lowe’s has the imperial brand for like 8$. My fancy flue probe temperature meter thing is at 18” above the stove.

How close should the damper be to the stove or the probe? Too close to the stove might melt the damper, too close to the probe might bugger up the probe temperature readings. Are either of these valid concerns?

Currently, to get the stove above 600 I need to run flue temps up near 900.

Thanks!

Curious, how hot is the flue temp with stove damper closed? How far open is it to get it to 900?

 

[bholler]

Curious, how hot is the flue temp with stove damper closed? How far open is it to get it to 900?

He hasn't run it with the damper yet

 

[hardcore]

Holy smokes. After 8 years, the slip section of single wall does not like to collapse and then gets stuck closed! Eventually got it with some lube and a hammer but while wiping all of the pipes down I did manage to remove lots of paint. Looks like I’ll need to repaint at end of season.

Since I had it apart, I swept the sections with an old fashion poly brush. Nice and brown, crunchy powder.

Damper is in. The seam on the single wall sometimes prevents full 360 degree turning but that’s okay. Kind of a nice stopper. Damper at 12” above stove, probe at 18”.View attachment 272536

I need to clean up. What a messy job. Then we’ll see how this thing works. I have no manometer so it will be just experimental.

I just put in a damper on my single wall pipe. Similar setup to your for my drolet legend III. Same issues. Need to repaint, dirty and my damper can't 360. It hits the seam on the rear. Overall though, when I'm drafting hard, I believe it improved my efficiency by about 15%.

 

[Highbeam]

He hasn't run it with the damper yet

Sure I have. Started about 2 hours ago but I’m definitely not very experienced with it yet.

Curious, how hot is the flue temp with stove damper closed? How far open is it to get it to 900?

So I filled up the stove, key wide open and it took just a few minutes to get to 750 flue temperature and then I swung the key fully closed. No problem. Fire less violent but still quite robust. Intake down about 25% and flue temps settled in at 700 as the stove temp rose to 600. I adjusted the intake down to about the normal cruise setting and stove was warmer than usual near 600 and flue temps were about 200 degrees cooler in the 600-700 range.

The fire is much more “in the firebox” than before and ghost flames actually happen now. Time will tell if the fuel lasts longer. I figure less temperature going up the stack and less flow rate of that heat has to mean efficiency goes up.

Oh, I tested opening the door with key closed. Smoke comes out for sure!

 

[Highbeam]

619 in flue, 545 stove top, robust fire with both primary and secondary flames. Key fully closed.

Should mention chimney is 10’ single wall, 9 feet class a, all vertical, 750’ asl, it’s in the 40s out.

So far I’m happy. I’m a little afraid that I’ll need to open the intake as the fuel load burns down to keep a clean burn. We’ll see.

 

[kennyp2339]

Nice @Highbeam I've been religiously using my key damper on the BK and could not be happier.

 

[brenndatomu]

I swung the key fully closed. No problem. Fire less violent but still quite robust

That particular damper appears to be a very "open" design...I bet you still have plenty of draft, but without putting a meter on it, no way to know exactly.
It won't take you long to see why us furnace guys are big on controlling draft...it makes a huge difference!

 

[Gearhead660]

He hasn't run it with the damper yet

Sorry for confusion. Meant primary air control on the stove. Before adding the flue damper .

 

[Hoytman]

You might need some double wall pipe now, maybe. Time will tell when you clean it after the season.
Nice looking set up. Is that your NC 30?

 

[Dieselhead]

If you have the damper close to closed and the stove decides to backpuff it will definitely get your attention!

 

[Highbeam]

If you have the damper close to closed and the stove decides to backpuff it will definitely get your attention!

I’ve never had a back puff on this nc30 install. Since this is in a shop it is almost always run on high output settings. Never choked down to where the flame goes out.

Do you think the damper makes backpuffs more likely?

Sorry for confusion. Meant primary air control on the stove. Before adding the flue damper .

So far, same stove intake settings get me same stove temperatures but cooler flue temperatures and longer lasting fuel.

That particular damper appears to be a very "open" design...I bet you still have plenty of draft, but without putting a meter on it, no way to know exactly.
It won't take you long to see why us furnace guys are big on controlling draft...it makes a huge difference!

This damper plate was more closed up than the alternative from imperial or others I found on the inter webs. I’m actually glad I can just swing it full closed rather than trying to be precise every time I close it. My chimney is not excessive so only a small reduction in draft is needed to get down to the sweet spot. If this was a furnace, and it might be someday, I would definitely spring for a manometer.

 

[brenndatomu]

Do you think the damper makes backpuffs more likely?

Not unless you close it "too far" and snuff the flame out...then, look out!

 

[Hoytman]

Not unless you close it "too far" and snuff the flame out...then, look out!

On my old pre-epa stove I used to close the damper and open the air controls more for when I needed more heat when it got below 15*F. Stove would throw crazybamounts of heat and get a secondary burn without air tubes. (Door was leaking slightly at the top. LOL!) You could tell when it would happen, the stove would go from a normal reload run of 425F to about 650F if I didn’t close the air intakes about 20 minutes after reload. I really never opened the spinners that much, so that door must have been leaking pretty good by the time I pulled the stove out of the house. Gaskets were new, but the door just latch needed heated and bent to tighten things back up.

 

[begreen]

Even though our F602 had a short flue system when it was in the house, the key damper made a big change with less heat going up the flue and a hotter stove. The difference was not trivial. It didn't have as strong of an effect on the F3CB when it replaced the F602.

 

[Highbeam]

Even though our F602 had a short flue system when it was in the house, the key damper made a big change with less heat going up the flue and a hotter stove. The difference was not trivial. It didn't have as strong of an effect on the F3CB when it replaced the F602.

I’ve definitely got the less heat going up the flue part but having trouble with the hotter stove. I’m trying a run with damper at 50%. That’s okay right? To run them partially closed?

25 this morning so plenty of draft to play with.

 

[Hoytman]

Should be able to adjust it however you need. Doesn’t need to be full open or full closed. Put it where you want it.

I clamp a small 4”-6” pair of vise grips to my handle. Stays cool and most importantly it’s extra insurance to keep it where I set it and keeps wind from changing it.

 

[begreen]

I’ve definitely got the less heat going up the flue part but having trouble with the hotter stove. I’m trying a run with damper at 50%. That’s okay right? To run them partially closed?

25 this morning so plenty of draft to play with.

Yes, no problem running with it partially open. We dipped down to 29 here. Guess my banana plant is going to be unhappy.

 

[Dieselhead]

I’ve never had a back puff on this nc30 install. Since this is in a shop it is almost always run on high output settings. Never choked down to where the flame goes out.

Do you think the damper makes backpuffs more likely?



So far, same stove intake settings get me same stove temperatures but cooler flue temperatures and longer lasting fuel.

This damper plate was more closed up than the alternative from imperial or others I found on the inter webs. I’m actually glad I can just swing it full closed rather than trying to be precise every time I close it. My chimney is not excessive so only a small reduction in draft is needed to get down to the sweet spot. If this was a furnace, and it might be someday, I would definitely spring for a manometer.

It’s hard to forecast backpuffs, it really has to be ideal conditions. With high output I doubt you would ever see one. Also I did think you were talking about damping your BK in your initial post, I didn’t look at the pics closely.

 

[Highbeam]

It’s hard to forecast backpuffs, it really has to be ideal conditions. With high output I doubt you would ever see one. Also I did think you were talking about damping your BK in your initial post, I didn’t look at the pics closely.

The Bk on a 12’ flue and with actual control of the intake air, I have no problems with overdraft. It’s just purring along right now while we expect snow tonight.

The nc30 has a huge secondary hole that is always wide open pouring air through the firebox as fast as the chimney can suck it. Right along with the heat which is why I’m trying to reel in the chimney.

 

[Dieselhead]

Yea my old ZC built in was like that, couldn’t dampen that thing down far enough.